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alpinelakespilot2000

Well Known Member
This was news to me, but perhaps not for all the rest of you who understand electricity..

I have been trying to figure out if my Odyssey battery is going to be up to the task of first start after having been abused during the 4 years I have had it in the build phase. I read the Odyssey charging instructions and they are very clear that the charger is NOT to connect directly to the negative terminal of the battery, whether the battery is in or out of the vehicle. Instead, if out of the vehicle, you must use a 24" piece of 6AWG attached to the battery and connect to that, or, if in the vehicle, the charger (-) clip is to be attached to engine block or other non-battery terminal ground. Although I never connect (-) clip to the weak battery when jump starting a car (using the frame of the car instead), this was news to me for battery charging purposes. Is this just an Odyssey thing, just an extra conservative precautionary thing, or are people who charge the Odyssey battery by connecting red alligator clip to (+) on the battery and black alligator clip to (-) on the battery doing damage to their batteries and/or their health? I've seen many charge their Odyssey this way, so I'm just curious.

Here's the manual...
http://www.odysseybattery.com/documents/US-ODY-CM-02_0107_000.PDF
Excerpt: "5. Connecting to a negative-grounded system: Connect the red (POSITIVE) output clamp to the POSITIVE post of the battery. Rock and twist the clamp back and forth to be sure a solid electrical connection is made. Then connect the black (NEGATIVE) output clamp to a heavy, unpainted metal part of the chassis or engine block, away from the battery (see figure left). DO NOT connect clamp to negative battery post, carburetor, and fuel line or sheet metal part."
 
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Negative connection

My read on the instructions you posted is "explosion potential" does exist from battery gases since they equate carburetor and fuel lines in the same context. It appears they feel 24" is a safe distance, assuming it is not curled back to the side of the battery !!
 
What's also kind of strange about their instructions is that, earlier in the same manual, they indicate that you can use the ring terminal pigtail adapter that gets attached permanently to both posts of the battery. How is connecting the charger to that any different than just hooking up the alligator clamps to both battery terminals?
 
They want you to make the last connection (the one that can spark) at some physical distance from the battery in order to reduce the chance of explosion.
 
wives tale?

I've often heard this and maybe it's a good suggestion for a battery that's just been seriously charged up in a closed compartment (hydrogen and oxygen gas), but would 24 inches really make a difference? Has anyone actually heard of battery exploding when connected to another assuming it wasn't connect wrong such as in series loop?

When I have had to jump another vehicle, I have never had good enough contact at anything other than both battery terminals.

Bevan
 
Bevan said:
I've often heard this and maybe it's a good suggestion for a battery that's just been seriously charged up in a closed compartment (hydrogen and oxygen gas), but would 24 inches really make a difference? Has anyone actually heard of battery exploding when connected to another assuming it wasn't connect wrong such as in series loop?

When I have had to jump another vehicle, I have never had good enough contact at anything other than both battery terminals.

Bevan
Click to expand...

Yes, it is enough to make a difference. I have jumped cars and boats this way for years, and haven't found it necessary to go directly to the terminals.

I have a degree of paranoia about this, because I see blinding and disfiguring injuries roughly once a year from this, most commonly in the winter when cars are having a hard time, or spring when people take their boats to the lake for the first time after winter hibernation.

Please learn to do this properly, make the last connection to a good ground remote from the battery (and break the circuit first away from the battery afterwards). Wear safety glasses anytime you are futzing around with a battery. Seriously.
 
Back when all cars had open cell batteries we would see plenty of underhood acid splatter evidence in the used car fleet.....more than enough to convince me batteries really do blow up. Don't see it so often today, I assume because of better (or total) battery sealing. Regardless, jumper cables are banned from my store just because I can't depend on employees to always follow the last-connection training.

Speaking of battery training.......when installing a battery how many of you always connect the negative last, or when removing a battery disconnect the negative before the positive?
 
Yep.

I'm with Dan on this one.

I saw the results of a battery explosion outside my wife's restaurant.

One of the cables was loose and when the owner turned the ignition key to "start", it arked and we heard the explosion from inside the restaurant....what a mess it made!

Best,
 
DanH said:
Speaking of battery training.......when installing a battery how many of you always connect the negative last, or when removing a battery disconnect the negative before the positive?
Click to expand...

I do, I do! Back during the build, I had a brain fart and put a wrench on the positive without disconnecting the negative. You wouldn't believe the size of the zap that occurred when the wrench touched the firewall! I now have a screw in the hole that was created when this happened!

So, don't forget to disconnect the negative ALWAYS ALWAYS ALWAYS when messing around with the battery terminals!
 
My father is 82 and turns 83 this year. He ran a service station when I was born. He always taught me to connect the negative jumper / charging cable to the frame last and not the battery plus to always disconnect the negative cable from the battery first and to hook the negative terminal up last.

I do it that way because that is how I was taught and have done it that way all my life.
 
Guys,
Take the advice seriously. If you don't believe it, watch an old film of the Hindenberg airship trying to dock at Lakehurst NAS. Same reaction, just smaller quantities at your airplane. Or car, or stationary engine driven generator, pump, or whatever. Batteries these days are much better at not leaking hydrogen, but not foolproof. 24" away might be good, because a hydrogen/oxygen mixture is just like a gasoline/oxygen mixture, if it is too rich or too lean, it won't ignite. Immediately out of the leak, the H2 gas is most concentrated, or richest, and after a short distance (how short depends on many variables, just remember that farther is better) may become too "lean" to ignite, i.e., not enough H2 molecules mixed with the O2 molecules to get a reaction, i.e. explosion, started. In between, an explosion (strictly speaking, what we are calling an "explosion" is more accurately called a deflagration, because the resulting pressure wave is subsonic, as opposed to a detonation, in which the pressure wave is supersonic, as with dynamite) is completely possible given an ignition source, such as an arc when the connection from the charger to the battery circuit is made, or when an open circuit from the battery to a switched on load in the airplane is closed, as when connecting the second battery cable to the battery post with the master switch left on.

Bottom line, always, always, always make the last connection or the first break in the circuit away from the battery.
 
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I too have seen quite an impressive explosion from jumping a battery directly. Connecting the negative at a distance from the battery seems prudent.
 
Lots of discussion about venting of gases from the battery but if his Odyssey battery is like mine (PC680) it does not have any vents to vent gas from.
 
I believe those Odyssey precautionary instructions are more oriented towards "jumping off" than charging, where you can't reasonably avoid making live connections. It's all about understanding what you're trying to prevent. It should be totally safe to:
  • Turn off and unplug the charger from the wall.
  • Short the positive and negative leads of the charger together to dissipate any residual charge.
  • Connect the charger's leads to the battery.
  • Plug in and turn on the charger.
There should be zero risk of spark if those simple precautions are taken.

- John
 
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This has always been the standard when jumping a car battery. The negative charger connection is connected to a metallic part of the engine block.

The way around this seems pretty clear to me: Don't make any battery charger connections while the battery charger is plugged in.
 
batteries

I have seen battery explosions twice and vowed to figure out why they happened. It seems to me that the different cells that make up the battery are connected at top and bottom by lead connections and the entire cell assembly is submersed in electrolyte to produce the energy. If the electrolyte level falls below the lead connections between the cells in the top of the battery and one of the connections is weak or broken, the battery will not function properly. Therefore a "jump start" is required to get things going again. When you attach the good battery to the bad one and a spark jumps from one cell to the other across the bad cell connection inside of the battery......Kaboom. The spark is not submersed under the electrolyte and the void area is filled with oxygen from the atmosphere and the gases produced by the battery. The explosion occurs from the inside of the battery out (of course). I don't believe that ignited fumes outside of the battery would be nearly as spectacular as the fumes ignited from inside.

My theory at least.
 
yea new guy here, just had to comment, in my younger and smarter days ( 17 ish and knew it all ) had to jump a car, now here is the kicker, it was a sealed batt, i DID connect the negative to the frame but none the less guess the cells were shorted out, BOOM cuts from the plastic case on my face ,arms and hands, acid in eyes and all over me and the car. was **** lucky, no scars, no loss of vision, but i think I needed new underwear.

so while you are doing all this and need to jump, hook up the DEAD batt first, so your not near it, should things go bad. also consider hooking up the batt, then plug in the charger. hope this saves someone else from my mistakes.
 
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